To examine the interrelation of marriage, parenting and infant development, 120 families will be studied between the last trimester of pregnancy and their infant's first birthday. Husbands and wives will be jointly interviewed regarding the effect on the infant on family functioning--prenatally and again at 3 and 9 months postpartum, and will individually complete marital quality questionnaires at these times. At 3 and 9 months, two naturalistic observations will be carried out in the home, one to assess mother-infant interaction and the other mother-infant, father-infant and husband-wife interaction. At the infant's first birthday, infant attachment to each parent will be assessed as will be infant exploratory competence. It is hypothesized that accurate prenatal expectations of the effect of the infant on family functioning will predict an easy transition to parenthood, and that quality of marital relations will be positively related to observed maternal and paternal behavior. In turn, highly involved and sensitive parents will produce securely attached infants, who are competent explorers.